Subtracting soldermask from silkscreen in Gerber files

Hi guys,

I’ve generated gerber outputs for my PCBs and realized that there are lots of areas where the exposed copper is covered by silkscreen, potentially preventing solderability. I know that some fabrication houses automatically subtract the (inverted) soldermask layer from the silkscreen layer but many don’t and I’d like to have a general solution to this problem. … p_id=33921 suggests that this feature has already been requested for gerbv and Gerbtool already has this feature but the latter seems to be very complicated and I’m clueless how to do layer subtraction.

I’m wondering whether your service automatically fixes this issue, but I’m also very interested about the solution itself so I’d definitely appreciate you describing how to do it.

Thanks in advance!


A while back I asked Seeed about the same thing. viewtopic.php?f=9&t=2257
I can now happily report the fabhouse that Seeed uses indeed does silk clipping. But I’d really like to be able to clean up the gerbers myself with Gerbv or any other utility…

This board was actually a test for three things. See if it was possible to do an Arduino Shield on the 5x5cm service, to see if the silk clipping was done properly and test what happens if you remove the top or bottom part of a thru-hole pad. (The answer is that the hole still gets plated as can be seen in the lower left corner of the pix below)

In eagle the board looked like this - with a lot of silk all over the pads.

When I got the boards back it was all cleaned up and nice.

Thanks a lot for the info, you’ve just made me learn that this feature is called silk clipping. :slight_smile:

I’m happy that Seeed does clipping but unhappy that there are still som fabhouses that don’t do clipping. I don’t really consider having a silkscreen over the pads a manufacturing error because if the available space is very tight then it’s almost unavoidable.